Wow excellent your hunting friend @kriptonik. Here below I will leave my opinion on the pros and cons of this product.

Pros:

• This product is very useful. It serves to improve the position of any person. Achieving a correct posture.
• It is a very easy product to use
• Function also through sound and vibrations
• In the same way you can strengthen much more the muscles of the back and the central muscles

Cons:

• I have not found any for this hunt.